At traditionally popular swimming holes along the Lester River, not a soul could be seen among the slow–moving, and in places stagnant, water.

...which is a good thing, says Sergeant Joseph Vidmar of the St. Louis County Rescue Squad, especially after the lack of rainfall, coupled with the frequent changes to the riverbed and shoreline.

"You don't often know the depth of the water. It's moving water, so that adds a [dangerous] factor," said Vidmar, standing in front of a handful of rescue boats at the rescue squad's base, "and there's no supervision; there's no lifeguards."

Sergeant Vidmar says that's why people should stick to places like Duluth's Park Point during a heat wave, like Stillwater residents Steve and Marlene Nelson did with their daughter Emma.

"We came up here from the Twin Cities thinking it would be a little cooler, but it really wasn't much cooler," laughed Marlene Nelson as the family stood by the beach.

Sergeant Vidmar says, for those making a day of it by the lake, you can never stress safety enough.

"We want to see that people often swim with a buddy, [and] have somebody with [them]. Parents: keep close supervision on your kids," said Vidmar, "and if you're out on a boat, wear a lifejacket at all times, and the same if you're doing any water sports, waterskiing."

And keep an eye on the latest rip–current conditions.

"Make sure that you have your green flag for... no riptides," added Vidmar, and all of which the Nelsons said they did Monday.

"[We] mostly [made] sure Emma was safe; she had a lifejacket," said Marlene Nelson.

And even though you're surrounded by all this fresh water at the beach, officials are quick to remind that it won't do a thing against dehydration, and that having a fresh water supply close by is crucial when it comes to beating the heat, "...because you're still at risk for heat stroke," said Vidmar.

...reminding us all that, when it comes to ways to beat this heat wave, there's really no such thing as too safe.

Health experts say that sunscreen or a light article of clothing on a sunny day, like a t–shirt, can be effective.

But new studies show that it could be the combination of the two that prove to be the most effective means of preventing that sunburn.